Why does my boyfriend keep doing this?

We've been going out for about 5 months now, but everytime he goes out somewhere with out me he comes back and says something like "There was a girl there, that kept looking at me, smiling, she was really flirty and pretty, any guy would like her.. but i seen your face and thought of the things you say, and i thought no i wont do it" ...I'm sorry? But am i wrong.. to think that isnt sweet??? ..because i find it a horrible thing to say and he expects me to be like "awww" .. am i wrong? Why would he say this..